Believe me, i am not the only person shooting T7 with very litte effect of the crud ring. It is IMO all in how you treat the bore and I am not sure I have any magic formula(s) it just works. Bore Coat say they have the the fix for it.

But in all honesty - i know a lot of folks battle the crud ring and I know I am fortunate and I am thankful for that.

I really believe it to be a chemical reaction of materials in the powder and in the bore. I even hate to say this on the open forum, but i first lost the crud ring when i settled on using BB in a hot bore many years ago that really reduced the harness of the ring. Then moving to synthetic oils further reduced it, such as Montana X-Tream BC, Slip 2000 or Eazox. The other thing that I think might help is the use of regular Windex with ammonia as a cleaner and patch swab at the range.

Also I wonder if elevation and humidity do not have something to do with it. But then I have been told about a group of guys in Pennsyvania that show no effects of the crud ring either so that blows my elevation theory....

I just do not know but again I am not the only one that is pretty much 'crud ring' free.